TWI398410B - Method for producing copper oxide from solution containing copper ions - Google Patents

Description

Producing copper oxide from copper-containing solution

The present invention relates to a method for producing copper oxide from a copper-containing solution, and more particularly to a method for producing copper oxide from an etching waste liquid and a micro-etching waste liquid in a circuit board process.

In the printed circuit board process, a lot of copper-containing waste liquid is produced, such as etching waste liquid generated in various etching processes. If the copper-containing waste liquid can be recovered and the copper or copper compound can be reduced and used, the environmental pollution can be reduced in addition to a large amount of cost.

In one of the prior art, the principle of precipitation of a metal ion compound is produced by using a solution at different pH values. For example, the cadmium ion (Cd ²⁺ ) has a pH of 9.8 or higher in the solution, the chromium ion (Cr ³⁺ ) has a pH of 6.5 to 9.2 in the solution, and the nickel ion (Ni ²⁺ ) in the pH of the solution. 9.3 or more, the pH of the zinc ion (Zn ²⁺ ) in the solution is 8.3 to 10.5, the pH of the iron ion (Fe ³⁺ ) in the solution is 3.5 or more, and the pH of the ferrous ion (Fe ²⁺ ) in the solution When it is 9.0 or more, the lead ion (Pb ²⁺ ) has a pH of 9.5 or more in the solution, and the aluminum ion (Al ³⁺ ) has a pH of 5.8 to 8.6 in the solution, which causes precipitation of the respective metal compound.

Among them, copper ions (Cu ²⁺ ) can produce basic copper chloride (CuCl ₂ ‧3Cu(OH) ₂ ), copper hydroxide (Cu(OH) ₂ ) and copper oxide (CuO) at a pH of 7.5. The mixture precipitates; and when the pH rises to 12.5, the basic copper chloride forms copper hydroxide and copper oxide.

In this prior art, the liquid copper is directly added to the copper-containing waste liquid and heated to raise the pH of the copper-containing waste liquid to 12.5, so that copper hydroxide and copper oxide can be precipitated; Filtration was carried out for 4 to 6 hours, and then baked by heating for 3 to 4 hours to dehydrate the copper hydroxide to obtain copper oxide.

However, when the pH of the copper-containing waste liquid rises to 12.5, in addition to the mixed precipitation of the copper hydroxide and copper oxide compounds, the remaining non-copper metal ions are precipitated into a mixture of the respective mixtures. For example, non-copper metal ions may come from soldering copper foil processes, additives in gloss agents such as arsenic (As), tellurium (Te) and bismuth (Bi); or roughening copper foil The agent used in the treatment is, for example, chromium (Cr), cobalt (Co), nickel (Ni) or zinc (Zn). In the etching process of the printed circuit board, the above metal is also dissolved in the copper-containing waste liquid to form impurities.

Since the aqueous copper hydroxide is viscous, the mixture of copper hydroxide and copper oxide obtained after the pressure filtration step of the filter press is extremely viscous and is difficult to handle. In the baking step, the purpose is to dehydrate the copper hydroxide to form copper oxide, but it is difficult to conduct the heat energy to the center of the mixture of copper hydroxide and copper oxide during baking, and only a part of the copper hydroxide can be made. Dehydration to form copper oxide. This prior art is not only time consuming, but the copper content of the obtained copper oxide is also only about 35%.

In another prior art, a water bath method is used in which an acid-base neutralized copper-containing waste liquid is circulated outside the heat exchange tube for 6 hours, and the heat exchange tube is indirectly heated by high-temperature steam to dehydrate the copper hydroxide. The copper oxide is subjected to pressure filtration through a plate and frame filter press and then baked once to obtain copper oxide having a copper content of approximately 70%. However, this prior art is still quite time consuming.

Therefore, it is necessary to provide a method for producing copper oxide from a copper-containing waste liquid to improve the above problems.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method for producing copper oxide from a copper-containing solution to obtain high-purity copper oxide.

The method for producing copper oxide from a copper-containing solution of the present invention comprises the steps of: obtaining a copper-containing solution; adjusting a pH of the copper-containing solution to form a first copper-containing solution having a first pH value and an iron-containing precipitate; a first pH value of the copper-containing solution to form a second copper-containing solution having a second pH value and a first copper-containing precipitate; forming the first copper-containing precipitate into a third copper-containing solution having a third pH value and a second copper-containing precipitate; and separating the third copper-containing solution and the second copper-containing precipitate, wherein the second copper-containing precipitate comprises copper oxide.

In one embodiment of the invention, the first pH is substantially between 3 and 6; the second pH is substantially between 7 and 8.5; and the third pH is substantially between 11 and 13.5.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

Please refer to FIG. 1 for a flow chart of the steps of an embodiment of the method for producing copper oxide from a copper-containing solution of the present invention.

As shown in Fig. 1, the present invention first proceeds to step S701 to obtain a copper-containing solution.

In one embodiment of the present invention, the copper-containing solution is an etching waste liquid or a micro-etching waste liquid generated in an etching process, but the invention is not limited thereto, and any solution containing copper ions (Cu ²⁺ ) may also be used. Copper oxide (CuO) is obtained by the method of producing copper oxide in a copper-containing solution of the present invention.

Next, in step S702, the pH of the copper-containing solution is adjusted to form a first copper-containing solution having a first pH value and an iron-containing precipitate.

In step S702, the pH of the copper-containing solution is adjusted to a first pH value. Since the copper-containing solution is acidic, a basic substance is added in this step to increase the pH of the copper-containing solution to the first pH. In an embodiment of the present invention, the alkaline substance is an aqueous solution of sodium hydroxide (NaOH), and the first pH is substantially between 3 and 6, but the invention is not limited thereto. In a preferred embodiment, the first pH is substantially 3.5. When the first pH of the copper-containing solution is within the above range, the iron ions (Fe ³⁺ ) in the copper-containing solution form a precipitate of iron, whereby the iron ions of the copper-containing solution can be removed.

In an embodiment of the present invention, step S702 may be subdivided into steps S7021 to S7023, as explained below.

In step S7021, a charge enhancer is added to the copper-containing solution.

In step S7022, a polymer flocculating agent is added to the copper-containing solution.

In an embodiment of the invention, both step S7021 and step S7022 are for strengthening iron ions to form ferrite precipitated in the copper-containing solution. In one embodiment of the present invention, the charge enhancer is Poly Aluminum Chloride (PAC), and the polymer aggregating agent is Diacetone Alcohol (DAA), but the invention is not limited thereto. In one embodiment of the invention, the iron is iron (Fe(OH) ₃ ), but the invention is not limited thereto.

Next, in step S7023, the copper-containing solution and the iron-containing precipitate are separated to obtain a first copper-containing solution having a first pH value substantially free of iron ions.

Next, in step S703, activated carbon is added to the first copper-containing solution and the activated carbon is removed after sufficient contact reaction.

In step S703, activated carbon is added to the first copper-containing solution to sufficiently contact the reaction, thereby adsorbing the organic matter in the first copper-containing solution into the activated carbon, and then removing the activated carbon to remove the first copper-containing solution. Organic matter in solution. In one embodiment of the present invention, the active carbon-based powdered activated carbon has a period of sufficient contact with the reaction for substantially one hour, but the invention is not limited thereto. In an embodiment of the present invention, the method of removing activated carbon may be suction filtration, but the invention is not limited thereto.

Next, in step S704, the first pH value of the first copper-containing solution is adjusted to form a second copper-containing solution having a second pH value and a first copper-containing precipitate.

In step S704, a basic substance is added to the first copper-containing solution, and the first pH value of the first copper-containing solution is increased to form a second copper-containing solution having a second pH value and a first copper-containing precipitate. In an embodiment of the invention, the second pH is substantially between 7 and 8.5, but the invention is not limited thereto. In a more preferred embodiment, the second pH is substantially 8. Wherein, the copper-containing solution forms a copper precipitate at the second pH condition.

In an embodiment of the invention, the first copper-containing precipitate comprises basic copper chloride (CuCl ₂ ‧3Cu(OH) ₂ ), copper hydroxide (Cu(OH) ₂ ), copper oxide and other copper compounds, However, the invention is not limited thereto.

Next, in step S705, the second copper-containing solution and the first copper-containing precipitate are separated, and the second copper-containing solution is removed.

In an embodiment of the present invention, the method of removing the second copper-containing solution may separate the second copper-containing solution and the first copper-containing precipitate by centrifugation, leaving only the first copper-containing precipitate, but The invention is not limited to this.

Next, in step S706, the first copper-containing precipitate is washed with water and the moisture of the first copper-containing precipitate is removed.

In one embodiment of the invention, the first copper-containing precipitate is washed with water and then the water contained in the first copper-containing precipitate is separated by centrifugation.

Next, in step S707, the first copper-containing precipitate is formed into a third copper-containing solution having a third pH value and a second copper-containing precipitate.

In step S707, the first copper-containing precipitate is first added to the pure water, and then the alkaline solution is added to increase the pH of the first copper-containing precipitate solution, so that the first copper-containing precipitate solution forms a third pH. The third copper-containing solution and the second copper-containing precipitate. In one embodiment of the invention, the third pH is substantially between 11 and 13.5, but the invention is not limited thereto. In a more preferred embodiment, the third pH is substantially 12. In an embodiment of the invention, the second copper-containing precipitate comprises copper hydroxide and copper oxide.

It should be noted that the basic copper chloride in the first copper-containing precipitate forms copper hydroxide, copper oxide and sodium chloride (NaCl) under the third pH condition of the third copper-containing solution.

Next, in step S708, the third copper-containing solution and the second copper-containing precipitate are separated.

In one embodiment of the present invention, the method of separating the third copper-containing solution and the second copper-containing precipitate may separate the third copper-containing solution and the second copper-containing precipitate using a centrifugal separator, leaving only the second Copper precipitate, but the invention is not limited thereto.

Next, in step S709, the second copper-containing precipitate is washed with water and the moisture of the second copper-containing precipitate is removed.

In one embodiment of the invention, the third copper-containing precipitate is washed with water and then the water contained in the third copper-containing precipitate is separated by a centrifugal separator.

Next, in step S710, the third copper-containing precipitate is heated by microwave to obtain crude copper oxide.

In step S710, a microwave can deeply enter the second copper-containing precipitate to dehydrate the copper hydroxide of the second copper-containing precipitate to form copper oxide; thereby, the second copper-containing precipitate can form a high purity crude oxidation. Copper, its copper content can reach more than 80%.

Next, in step S711, the crude copper oxide is pulverized to form a copper oxide powder.

In step S711, the crude copper oxide is pulverized using a pulverizer to obtain copper oxide powder. In an embodiment of the present invention, the pulverizer has a dust collector to reduce dust pollution to the outside, and the particle size of the copper oxide powder is substantially between 100 mesh and 250 mesh, but The invention is not limited thereto.

Next, in step S712, the copper oxide powder is placed in pure water and subjected to ultrasonic cleaning.

In the step S712, another purpose of using ultrasonic cleaning is to re-form the fine copper oxide powder when the copper oxide powder is washed.

Next, in step S713, the copper oxide powder is removed from moisture.

In step S713, the method of removing moisture from the copper oxide powder may use a centrifugal dehydrator to remove moisture from the copper oxide powder, or wash the copper oxide powder with a low carbon number alcohol to remove moisture contained in the copper oxide powder, but the present invention Not limited to this. For example, a method of removing moisture from copper oxide powder may be mixed with a centrifugal dehydrator and a low carbon number alcohol.

In one embodiment of the invention, the lower carbon number is methanol (CH ₃ OH), but the invention is not limited thereto. In one embodiment of the present invention, after the copper oxide powder is washed with a low carbon number alcohol, the copper oxide powder may be further heated by microwave to remove residual low carbon number alcohols and moisture.

An example of a method of producing copper oxide from a copper-containing solution using the present invention will be described below.

The copper-containing solution used was a copper chloride etching waste liquid having a volume of 500 ml (ml); and the alkaline solution was a 40% sodium hydroxide solution. When the pH of the copper-containing solution was adjusted to the first pH value, a basic solution of 196 ml (ml) was added to the copper-containing solution to form a first copper-containing solution, the first pH value of which was actually 3.5. Next, powdered activated carbon was added to the first copper-containing solution, and stirring was continued for 1 hour, and then the powdery activated carbon and the iron-containing precipitate were removed by suction filtration.

Adjusting the pH value of the first copper-containing solution to the second pH value, adding 50 ml (ml) of the alkaline solution to the first copper-containing solution to form the second copper-containing solution and the first copper-containing precipitate, the second The second pH of the copper solution was actually 8.02. After the first copper-containing precipitate is taken out and washed with water, 1000 ml (ml) of pure water is added to form a first copper-containing precipitate mixed solution, followed by adding 13 ml (ml) of the alkaline solution to the first copper-containing precipitate to be mixed. The solution forms a third copper-containing solution having a third pH and a second copper-containing precipitate, and the third pH of the third copper-containing solution is actually 11.52.

The second copper-containing precipitate was taken out and washed with water, and the (dry) weight of the second copper-containing precipitate after washing was 95 g (g). Then, microwave heating was carried out, and the power of the microwave was 350 W for 30 minutes to obtain crude copper oxide. Next, the crude copper oxide was pulverized to form a copper oxide powder, and subjected to ultrasonic cleaning to obtain a (dry) weight of the copper oxide powder of 95.44 g (g).

The copper oxide powder was then dehydrated using methanol in a volume of 200 ml (ml), followed by microwave heating for 15 minutes. The weight of the copper oxide powder is finally obtained to be 88.25 g (g), wherein the copper content can be as high as 82.6%.

To sum up, the present invention, regardless of its purpose, means and efficacy, shows its distinctive features of the prior art. You are requested to review the examination and express the patent as soon as possible. It should be noted that the various embodiments described above are merely illustrative for ease of explanation, and the scope of the invention is intended to be limited by the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow chart showing the steps of a method for producing copper oxide from a copper-containing solution of the present invention.

Claims (11)

A method for producing copper oxide from a copper-containing solution, comprising the steps of: obtaining the copper-containing solution; adjusting a pH of one of the copper-containing solutions to form a first copper-containing solution having a first pH value, wherein Under the condition of the first pH, one of the copper-containing solutions, iron ions (Fe ³⁺ ), forms an iron-containing precipitate for separation. Adjusting the first pH of the first copper-containing solution to form a second copper-containing solution having a second pH and a first copper-containing precipitate, wherein the second pH is substantially between 7 and 8.5; forming the first copper-containing precipitate into a third copper-containing solution having a third pH value and a second copper-containing precipitate; and separating the third copper-containing solution and the second copper-containing precipitate, Wherein the second copper-containing precipitate comprises copper oxide (CuO). A method of producing copper oxide from a copper-containing solution as described in claim 1, wherein the first pH is substantially between 3 and 6. A method of producing copper oxide from a copper-containing solution as described in claim 2, wherein the third pH is substantially between 11 and 13.5. The method for producing copper oxide from a copper-containing solution according to claim 1 or 2, wherein the step of adjusting the pH of the copper-containing solution to form the first copper-containing solution having the first pH value The method further comprises the steps of: adding a charge enhancer to the copper-containing solution; adding a polymer aggregating agent to the copper-containing solution; and filtering the copper-containing solution. A method for producing copper oxide from a copper-containing solution as described in claim 4, wherein the copper-containing solution is filtered to remove the iron compound and form the first copper-containing solution having the first pH value. After the step, the method further comprises the steps of: adding an activated carbon to the first copper-containing solution and removing the activated carbon after sufficient contact reaction. A method for producing copper oxide from a copper-containing solution according to claim 1 or 2, wherein the first copper-containing precipitate comprises basic copper chloride (CuCl ₂ .3Cu(OH) ₂ ), and hydroxide Copper (Cu(OH) ₃ ), copper oxide or other copper compound. The method for producing copper oxide from a copper-containing solution according to claim 1, wherein the first pH value of the first copper-containing solution is adjusted to form the second copper-containing material having the second pH value; After the step of the solution and the first copper-containing precipitate, the method further comprises the steps of: separating the second copper-containing solution and the first copper-containing precipitate, and removing the second copper-containing solution; and removing the first The copper precipitate is washed with water to remove the moisture of the first copper-containing precipitate. The method for producing copper oxide from a copper-containing solution according to claim 1 or 7, wherein the second copper-containing precipitate further comprises copper hydroxide, and separating the third copper-containing solution and the second After the step of containing the copper precipitate, the method further comprises the steps of: removing the water of the second copper-containing precipitate after washing the second copper-containing precipitate; and heating the second copper-containing precipitate by microwave to obtain a crude Copper oxide. The method for producing copper oxide from a copper-containing solution according to claim 8, wherein after the step of heating the second copper-containing precipitate in the microwave to obtain the crude copper oxide, the method further comprises the steps of: pulverizing the crude Copper oxide to form a copper oxide powder, wherein the copper oxide powder has a particle size substantially between 100 mesh and 250 mesh; the copper oxide powder is placed in water and subjected to ultrasonic cleaning; And removing the copper oxide powder from moisture. A method for producing copper oxide from a copper-containing solution according to claim 9, wherein in the step of removing moisture from the copper oxide powder, the copper oxide powder is removed by using a centrifugal separator or A low carbon number alcohol is sufficiently contacted to react the copper oxide powder and further separated to remove moisture contained in the copper oxide powder. The method for producing copper oxide from a copper-containing solution according to the first aspect of the invention, wherein the copper-containing solution is one of an etching waste liquid and a micro-etching waste liquid in a circuit board process.